This invention relates to a methods of producing medical devices such as prosthetic and orthotic structures and, in particular, to a method of manufacturing such devices in a manner that makes the devices more widely available to the public at less cost.
The manufacture of medical devices such as prosthetic and orthotic structures is well known in the art and described for example in European Patent No. EP 0 555 207 which issued to Clynch Technologies Inc. on Oct. 11, 1995, and its United States counterpart, U.S. Pat. No. 5,432,703 which issued to the same patentee on Jul. 11, 1995. These patents describe a system and a method for producing a medical device such as a prosthetic or orthotic structure having a surface for engagement with a portion of the human body. The system produces a more accurately fitting socket and involves a less time-consuming process with less discomfort to the patient than other prior art methods. The socket is made from a mold that is produced from a three dimensional image of the portion of the body requiring the medical device. The three dimensional image is obtained by scanning the body surface requiring the device, the body surface being supported within a reflective, stretchable stocking on which non-reflective markings are placed to indicate sensitive areas of the body surface as well as insensitive areas capable of bearing a load. The scanned image therefore includes void-points coincident with the non-reflective markings on the stocking surface. The digitized image is manipulated to produce a modified digital image by selectively adjusting certain discreet modification sites to produce areas of enlargement and adjusting other discreet modification sites to produce areas of reduction. A mold is produced from the modified data by converting the data into control code for controlling the operation of a machine for producing the mold using the image data. An orthotic structure is manufactured using the mold whereby the areas of enlargement correspond to non-load bearing modification sites and the areas of reduction correspond to load bearing modification sites so that sensitive areas of the body part are relieved of pressure and load bearing areas of the body part are positioned at the areas of reduction to facilitate load bearing. This method has proven to be very effective in producing custom fitted prosthetic and orthotic devices which are comfortable to wear and provide extended service.
In spite of the recognized advantages of this method, laser digitizing equipment is expensive. Public access to the benefits of the invention is therefore curtailed.
It is therefore a primary object of the present invention to provide a method of producing medical devices such as prosthetic and orthotic devices which reduces the cost of production and makes the benefits of the technology more widely available to the general public.
It is a further object of the invention to provide a method for producing a medical device such as a prosthetic or orthotic structure more economically without sacrificing the optimal custom fit that may be obtained using a digitized three dimensional image that is modified at selected sites to provide maximum comfort.
These and other objects of the invention are achieved by a method for producing a structure for use in a prosthetic, orthotic or other medical device having a surface for engagement with a portion of the human body, including the steps of defining the body portion and presenting an outer surface thereof for laser digitizing, inspecting the body portion and identifying critical areas on the outer surface with small non-reflective markings, scanning the body portion with a laser digitizer to produce a plurality of closely spaced longitudinal lines read by the laser digitizer, storing the contour coordinates representing a digital image as data including void-points produced by the non-reflective markings, displaying the digital image graphically and identifying basic modification areas for said inner surfaces of said structure by way of the location of the void-points, identifying selected vertices within the basic modification areas, producing modified data by moving the selected vertices for some of the basic modification areas in a positive direction relative to non-selected surrounding vertices to produce build-ups and moving selected vertices of other basic modification areas in a negative direction relative to non-selected surrounding vertices to produce areas of reduction, using said modified data to produce control code for controlling a machine for producing a mold having a surface contoured in the likeness of the body surface, but including areas of build-up and areas of reduction, and producing the structure from the mold whereby the areas of build-up provide areas of relief in the surface of the structure and the areas of reduction provide higher pressure areas in the surface of the structure, the improvement comprising:
covering the surface of the body portion with a conformable reflective material that can be activated to make a model of the body portion;
inspecting the body portion and identifying critical areas on the material with non-reflective markings;
activating the material to harden and produce the model of the body portion;
removimg the model from the body portion and scanning the model to produce a digitized image of the model;
shrinking the digitized image to accurately represent the body portion by compensating for the thickness of the model; and
manipulating the compensated digitized image to provide areas of build-up and relief in the medical device, whereby the manipulated compensated digitized image is used to produce code for controlling a machine for producing a mold or an anthropometric device having a surface contoured in the likeness of the body portion, but including the areas of build-up and relief.
The method in accordance with the invention therefore provides a mechanism for decentralizing most of the process of producing medical devices such as prosthetic or orthotic structures as well as other anthropometric devices. The decentralization is enabled by the use of a conformable reflective material which can be used to make a substantially rigid model of the body portion requiring the medical or anthropometric device. Such a model can be made in a physician""s office or clinic without the use of expensive equipment. The model is produced by covering the surface of the body portion with the conformable reflective material that can be activated to form a hardened structure. Preferably, the conformable reflective material is impregnated with a plastics resin which is activated by the application of water. In accordance with the procedure, the body portion is covered with the conformable reflective material and critical areas of the covered body portion are identified on the material covering with non-reflective markings. The non-reflective markings are preferably applied before the material is activated to harden and produce a model of the body portion. This permits the physician or prosthetist to palpate the bony areas of the body portion to determine the exact location of critical areas before the material is hardened to form the model. After the critical areas are indicated by the non-reflective markings, the material is activated to harden or produce the model. Once the model has hardened, it is removed from the body portion and shipped to a scanning facility which scans the model to produce a three dimensional image, for example, in the manner described above in the European and United States patents to Clynch Technologies Inc. The three dimensional image is thereafter preferably downloaded to a computer system of the physician which produced the model. The physician""s computer system is equipped with a custom computer aided design (CAD) software application which permits the image to be manipulated and modified with the assistance of a database of default modifications for each modification site indicated by the non-reflective markings. After the digitized image is modified to provide a custom fit most suited for the body part, the image is uploaded by the physician to the scanning center where it is converted into control code for controlling a machine for producing a mold, such as a milling machine for example. The control code is then uploaded to the machine for producing the mold and a mold is produced using the control code. In certain instances, a mold is not produced. Instead, an anthropometric device is produced directly by the machine using the control code. This is the case when a device such as a custom arch support, a custom seat or the like is produced from the scanned image of the model. The milling machine may be located at the scanning facility or, alternatively, at a device manufacturing facility which produces the medical or anthropometric device. Regardless of where it is located, the device manufacturing facility uses the mold and related specifications to produce the medical or anthropometric device, which is shipped to the physician""s office for any final fitting and/or adjustments that may be required.
In the method in accordance with the invention, a scanning facility preferably serves a plurality of physician""s clinics which communicate with the scanning facility via a telecommunications service such as the Internet or by a couriered medium such as diskette or CD Recordable. Furthermore, a plurality of scanning facilities may be served by a single device manufacturing facility which may also communicate with the scanning facilities by a telecommunications service such as the Internet or a hard storage medium exchanged by courier or the like. The invention thus permits a much wider distribution of the technology because it obviates the requirement for expensive image digitizing equipment at every service provider""s clinic and permits patients to be treated by local physicians who have access to the technology at minimal cost.